Thread: How hot is too hot? TD5 Engine

Originally Posted by Young1

Hi guys, I have recent installed a coolant temperature gauge and have a few observations that I though you might be interested in. just completed a 5000km trip.

• Coolant operating temperature settles at 96 deg.
• When driving at 100 km/h, sits around 98 deg.
• When driving at 110 km/h, sits around 102 deg.
• When driving on sand dunes in Lo or Hi, sits around 96-100 deg.
• Always cools down quickly after slowing down (or idling) to 96 deg in 2-3 minutes.

As far as i can tell it still has the OEM Thermostat installed. Which full opens art 96 deg, so make sense that it remains at this temp.
Rave thermostat.jpg

These observations are very consistent for all ambient temperatures, from 1 deg mornings to 30 deg days. Some days as much as 600 kms travel.

2004 Discovery 2 TD5 280k kms, Not Towing anything.
EGR Removed, New Expansion tank & Cap, New-ish Viscous fan, No other mods.

G'day Hayden - panic not! The TD5 is designed to run up to 120 C - from one of our real gurus here in Blknight.

Mine used to get up to 115 for short periods in really heavy slow/offroad towing conditions. I normally set the Nanocom for about 107 C - in normal running it would be about the same as your readings

My TD5 has a big arsed alloy radiator.
It seems to run, once up to speed, anywhere from 88 to 98 depending on sped, hills & ambiant temps.
I see via the Nanacom when the thermostat opens & closes.
My only worry is I never hear the fan really wind up, other cars I've had with a viscous fan I would hear it roar at the crest of hills etc.
I never hear this one? Maybe my age & poor hearing from to many bangs on the head.
Jonesfam

Originally Posted by jonesfam

My TD5 has a big arsed alloy radiator.
It seems to run, once up to speed, anywhere from 88 to 98 depending on sped, hills & ambiant temps.
I see via the Nanacom when the thermostat opens & closes.
My only worry is I never hear the fan really wind up, other cars I've had with a viscous fan I would hear it roar at the crest of hills etc.
I never hear this one? Maybe my age & poor hearing from to many bangs on the head.
Jonesfam

G'day Paul.

Would you like to join my club?

I don't recall ever hearing the fan wind up on mine either, either pre or post big alloy fan

so long as the cooling system is in good nick (and this is from memory)

water boils at 100 degrees, presurise it to ~14psiG and you're good to maintain liquid in the cooling system till it hits ~118c.

most coolant when at the correct concentration will hold up to about 128 degrees at the same pressure,

once you hit that limit.... you're still adding heat and everything is trying to get rid of it for you however you're still adding latent heat to the system... effectively causing the pressure to rise (and then the temp) until the cap vents, once thats happening so long as you have liquid in the system you're still ok.... Till something lets go and the pressure comes off then the water turns nearly instantly to steam ejects most of itself and you're now trying to cool the engine using steam, and that never really worked well for anyone using aluminium on top of a fire.

Whats really important is how the engine is behaving, and to me it looks like your system is doing just what it should. If it were me and I really wanted to worry about what you have. IF you have the secret hidden heater hose still fitted, give the system a flush out, change that hose (or all of them, may as well) relocate the hose clamps to make changing them later easier and fill it up with nice clean demin water and coolant of spec/choice or the correct premix coolant of spec/choice.

I reccomend the nulon red for the td5, but like all of the OEM original OATs, it can be a bugger to keep in so HOAT's are a good option and if you cant get anything else the standby is tectaloy extra cool. but you need to change that fairly frequently. Nulon red OAT was always good for 3 years unless you cooked it or couldn't keep it in the system.

Originally Posted by gavinwibrow

I don't recall ever hearing the fan wind up on mine either, either pre or post big alloy fan

TD5 is pretty noisy,so its difficult to hear.

Used to hear mine very rarely,but always going from East to West, in hot weather, on the track across Moreton island.It was going up the long uphill soft sand section,in a cutting,so the noise bounced off the walls of the cutting.Fan would cycle up and down.

FWIW those with D3/4,they do a self check and roar at every so many starts.Viscous with electric over ride.

Originally Posted by Blknight.aus

so long as the cooling system is in good nick (and this is from memory)

water boils at 100 degrees, presurise it to ~14psiG and you're good to maintain liquid in the cooling system till it hits ~118c.

most coolant when at the correct concentration will hold up to about 128 degrees at the same pressure,

once you hit that limit.... you're still adding heat and everything is trying to get rid of it for you however you're still adding latent heat to the system... effectively causing the pressure to rise (and then the temp) until the cap vents, once thats happening so long as you have liquid in the system you're still ok.... Till something lets go and the pressure comes off then the water turns nearly instantly to steam ejects most of itself and you're now trying to cool the engine using steam, and that never really worked well for anyone using aluminium on top of a fire.

Whats really important is how the engine is behaving, and to me it looks like your system is doing just what it should. If it were me and I really wanted to worry about what you have. IF you have the secret hidden heater hose still fitted, give the system a flush out, change that hose (or all of them, may as well) relocate the hose clamps to make changing them later easier and fill it up with nice clean demin water and coolant of spec/choice or the correct premix coolant of spec/choice.

I reccomend the nulon red for the td5, but like all of the OEM original OATs, it can be a bugger to keep in so HOAT's are a good option and if you cant get anything else the standby is tectaloy extra cool. but you need to change that fairly frequently. Nulon red OAT was always good for 3 years unless you cooked it or couldn't keep it in the system.

14 psi is about 1 bar, or normal atmosphere pressure at sea level at 23 ish degrees?

Do you mean an additional 14psi?

DL

Originally Posted by 350RRC

14 psi is about 1 bar, or normal atmosphere pressure at sea level at 23 ish degrees?

Do you mean an additional 14psi?

DL

PSI is usually PSIg (psi Gauge) and is typically pressure over atmospheric
PSIA is absoulute pressure and includes the atmospheric pressure.


working whole numbers

14psi=14PSIg=28psiA

autotmotively..

those vacuum/boost gauges you can buy are simply a PSIa gauge thats been recalibrated to read as PSIG

td5's are an annoying beast, the cooling system works in PSIg some engine pressure numbers are PSIG and others are PSIA.